Various types of mechanisms have been known to exist in the prior art which allow one to determine the depth of a hole that is being drilled into a surface.
An example of such a device, certainly within the field of the invention described herein below, includes the following patent: U.S. Pat. No. 4,113,404 Lippacher et al.
This and other devices similar to it can be characterized by noting that while an indication can be given as to the degree to which a drill bit has been used in boring into a surface, in many cases it is desired to provide the hole thus drilled at a specified angle relative to the surface upon which the drill is being worked so that the accurate depth to which the drill bit has been put can be known. Of course, if the drill is being held at an angle other than that which is desired, although the drill hole will be to the requisite depth, it is quite unlikely that the drill will have placed the hole at the proper angle which can have critical consequences.